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--- dump_spi_flash [2021/04/14 18:47] – add in-circuit kingkevin
+++ dump_spi_flash [2021/04/14 19:14] – [J-Link] kingkevin
@@ Line 214: / Line 214: @@
 Providing 5.0V on 3.3V or 1.8V power rails might damage any of the devices using this power rails.
 Also don't forget to drive the MCU reset line (if this is the solution you are using) since the programmer won't do it.
+==== J-Link ====
+The [[jtag#segger_j-link|J-Link]] is a JTAG programmer, but it recently also got [[https://www.segger.com/products/debug-probes/j-link/tools/j-flash-spi/|SPI programming capabilities]].
+{{:spi_flash:J-Link_BASE.jpg?0x200|}}
+It particularly fits in-circuit programming because it uses the target power instead of providing it, supports 1.8-5.0V, and provides a nRST output to hold the MCU under reset.
+It also allows to [[https://wiki.segger.com/J-Flash_SPI#Custom_Command_Sequences|perform some operations]] before and after talking to the flash chip.
+While it provides a pin to hold the MCU under reset, is does not provide a pin to release reset from the SPI flash chip (which also often has a nRST/nHOLD pin).
+You will have to pull is up yourself if the board doesn't do it already.
+Note that you need hardware [[https://wiki.segger.com/Software_and_Hardware_Features_Overview|version 10 or later]].
+Hardware version 8 does not support SPI flashing, and version 9 releases nCS just before talking to the chip (this seems to be an issue [[https://www.segger.com/downloads/jlink/ReleaseNotes_JLink.html|fixed for version 10 with software version 6.86c from 2020-10-06]] but is still present as of 2021-04-14 with firmware version 2021-02-02 and software version 7.00 from 2021-04-08, and setting CS in the init steps does not solve the issue).